/*
 * Copyright (c) 2023-2025 elsfs Authors. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.elsfs.cloud.common.mybatis.ext.sql.support.group;

import java.util.Collection;
import java.util.stream.Collectors;
import lombok.RequiredArgsConstructor;
import org.elsfs.cloud.common.util.lang.NamingCase;

/** 标准分组实现 */
@RequiredArgsConstructor
public class StandardGroupBy implements GroupByItem {

  /** 字段名称 */
  private final Collection<String> fields;

  /**
   * 构建SQL片段
   *
   * @return SQL片段
   */
  @Override
  public String buildSqlFragment() {
    return String.format(
        "GROUP BY %s",
        this.fields.stream().map(NamingCase::toUnderlineCase).collect(Collectors.joining(", ")));
  }
}
